McCulloch Chain Saws

[heimannm]

This information was initially compiled by Eccentric, not sure who else may have contributed.

Front Tank Mac

-Open piston pin bearing: Koyo B-88. Wrist pin bearings Koyo B-88 open, M871 closed

-Closed piston pin bearing: Koyo M-871.

-FW seal: 50663. SKF/CR 6763. Possibly also SKF 6522 (unconfirmed)

-PTO seal for ball bearing saws: 104432. SKF 6640. SKF 6816.

-PTO seal for needle bearing saws: 104128. SKF 7414.

-FW Bearing: 100824. POSSIBLY the same as 66016 as used on the top tank saws....and POSSIBLY 6203 C3. Will investigate.....

-PTO Bearing for ball bearing saws: 100824. See above.

-PTO Bearing for needle bearing saws: 104129.

Top Tank Mac

-F/W inner seal: 57898. Aftermarket? 30x17x7

-F/W outer seal: 57897. Aftermarket?

-PTO seal: 104432 or 104486. SKF 6640. SKF 6816. 35x17x7

-Bearings: 66016. IIRC they are 6203 C3 bearings. Will confirm /update.


Mark

 

[matt_lamb_160]

For the pin bearings a number of companies make the bearing numbers listed. The piston in my hand seems to read "Torrington B-87" and "Torrington M-881". B-88 is wider (1/2" instead of 7/16") and M-871 is narrower (7/16" versus 1/2").

For the 50633 seals, based on internet notes the Timken (474261 and 254270) are better than the SKF?

I have 6203 marked bearings on one of my cranks (I think a 380 crank). It is a front tank double ball bearing crank.

I am still chasing an equivalent for the 104129 bearing but think it might be a B-1210.

My total notes for front tank saws are (no guarantees):

Bearings
Piston Pin: 104378 and 101206 (Koyo, Timken and others B-87 and M-881)
Journal needle bearing: 104129 (B-1210; NSN 3110-01-037-9239)
Journal ball bearing: 100824 (Timken and others 6203 C3)
Seals
Crank seals ball bearing: 50663 (Timken: 474261)
Crank seals needle bearing: 104128 (Timken: 254270)

 

[clint53]

I really doubt this will work.
I shall see.

 

[matt_lamb_160]

More pics.
View attachment 889975

Did you drill the missing transfer port? If so, did you drill the matching transfer port on the other slide of the cylinder?

 

[Woodslasher]

Did you drill the missing transfer port? If so, did you drill the matching transfer port on the other slide of the cylinder?

Yes, and no(t yet?). I did not drill out the matching port as I don’t know a good way to fill in the hole if I drill it through the block, and I don’t have the means to drill inside the cylinder.

 

[pastryguyhawaii]

The owner of the property where I work pulled this 47 out of an old storage shed. I usually don't work on these older saws but this one has my interest. Will be my only gear drive. I have an IPL on the way so hopefully I can get it running. Looks to have had little use.

 

[matt_lamb_160]

Yes, and no(t yet?). I did not drill out the matching port as I don’t know a good way to fill in the hole if I drill it through the block, and I don’t have the means to drill inside the cylinder.

Well, you are committed now. The ports need to be balance so you need to drill the other side. I am keen to see what you come up with.

I don't think the reed bypass ports will be drilled on that saw either? If you get keen, you might like to read this:

 

[Woodslasher]

Well, you are committed now. The ports need to be balance so you need to drill the other side. I am keen to see what you come up with.

I don't think the reed bypass ports will be drilled on that saw either? If you get keen, you might like to read this:

Looks like I’ll be looking for some expansion plugs, then. That article is fascinating, thank you for posting it!

 

[matt_lamb_160]

Yeah, it is a great article. I wish I could find one like it for each series of engine.

 

[Little Jerrry]

Gents

Trying to get this 7-10A I restored a while back fired up (had it mounted on the wall while I waited for parts and just left it there) and had a couple of questions I was hoping you could help with:

1) I installed a replacement fuel line (not installed in picture) but it seems too long and kinks, it said it fits all the 10 series. Is there a trick to this or have I just got the wrong line? Normally I'd just throw on different line but these macs have that unique sealing part of the line between the tank and the carb area. If I cut the line short Im not convinced the hose will fit over the carb barb.

2) I believe I have the SDC58 carb. I only seem to have an idle speed adjustment needle.Does this carb not have a H /L adjustment? The saw will idle for a few seconds if I squirt fuel into it, but it wont rev at all, just stalls out.

3) Unfortunately it leaks fuel from underneath...a nice surprise after filling it up. It has been a while since I built this - is there just a rubber piece between the intake port and the carb that isn't sealing right? That can be the only source of a leak from underneath?

 

[Maintenance supervisor]

Gents

Trying to get this 7-10A I restored a while back fired up (had it mounted on the wall while I waited for parts and just left it there) and had a couple of questions I was hoping you could help with:

1) I installed a replacement fuel line (not installed in picture) but it seems too long and kinks, it said it fits all the 10 series. Is there a trick to this or have I just got the wrong line? Normally I'd just throw on different line but these macs have that unique sealing part of the line between the tank and the carb area. If I cut the line short Im not convinced the hose will fit over the carb barb.

2) I believe I have the SDC58 carb. I only seem to have an idle speed adjustment needle.Does this carb not have a H /L adjustment? The saw will idle for a few seconds if I squirt fuel into it, but it wont rev at all, just stalls out.

3) Unfortunately it leaks fuel from underneath...a nice surprise after filling it up. It has been a while since I built this - is there just a rubber piece between the intake port and the carb that isn't sealing right? That can be the only source of a leak from underneath?


View attachment 890441

Install spring in fuel line, no kink
Classic high speed check valve, idles then dies when throttle is stabbed.

 

[Greyman]

Apologies from a newb if this had been answered further back in the thread:

Do new guide bars with the D176 mount bolt right on to the midsize late model macs like the pm 10-10, pm 700, sp 81, etc? Or do you still need to bubba them up to get oil to the chain?

Also, are Internet the rumors of someone making full wrap top handles over here true?

 

[Little Jerrry]

Looking at the carb a little closer it seems to have a 61 stamped on it so it may not be the 58 that I first thought.

I did a pressure test on the SDC carb and it failed, had a slow leak and bubbles were coming out of the bottom left hole in this pic...does that mean anything in particular that its leaking there or just that the needle isnt seating right?



Also I noticed the carb has a "L" stamping...can I stick a screwdriver in the hole above the "L" and adjust things? I cannot see clearly enough whether whatever is in there is designed to be manually turned/adjusted



Appreciate any help gents.

 

[Little Jerrry]

Well one problem solved, I realised I had the bloody choke on (I should stick to my day job), no wonder it stalled when I pulled the throttle...I got it to rev when putting fuel down the carb which is good...I still have the leak but it looks like it was from that fuel tank cork gasket weeping down the side and under the saw. Ordered a new gasket from the USA and one of those grommets so I can run normal fuel hose.

Carb still leaks from the orifice above but the saw runs with fuel down its throat, but isnt drawing fuel from the tank...now the kinked line may be the issue...if the fuel tank isnt air tight will that impact its ability to pull fuel if the fuel line isnt 100% submerged?

Feels good to know the saw runs at least after the effort to rebuild it all and I can sort out these little peripheral issues .

 

[vinnywv]

Looking at the carb a little closer it seems to have a 61 stamped on it so it may not be the 58 that I first thought.

I did a pressure test on the SDC carb and it failed, had a slow leak and bubbles were coming out of the bottom left hole in this pic...does that mean anything in particular that its leaking there or just that the needle isnt seating right?

View attachment 890509

Also I noticed the carb has a "L" stamping...can I stick a screwdriver in the hole above the "L" and adjust things? I cannot see clearly enough whether whatever is in there is designed to be manually turned/adjusted

View attachment 890510

Appreciate any help gents.

Jerry, the cork gasket may seal up just fine after you get fuel on it. They dry out. New fuel they sometimes will swell back up and seal off. Not always but you may get lucky there.

The carb "L"..that carb has a fixed high jet needle. Non adjustable without changing the oriface. The angled adjustment is the low mixture adjustment. The holes on the side are blank. Theres nothing there.

If you have a small tank gasket leak it should still run. If your fuel line is not submerged it could starve for fuel and be very erratic. Running fast. The kink would be similar, starving for fuel. Get that figured out.

The air leak on the carb sounds like a gasket. It will effect it to some degree. Get a rebuild kit and call it done. Hope that helps you out some. Good luck.

 

[Maintenance supervisor]

Well one problem solved, I realised I had the bloody choke on (I should stick to my day job), no wonder it stalled when I pulled the throttle...I got it to rev when putting fuel down the carb which is good...I still have the leak but it looks like it was from that fuel tank cork gasket weeping down the side and under the saw. Ordered a new gasket from the USA and one of those grommets so I can run normal fuel hose.

Carb still leaks from the orifice above but the saw runs with fuel down its throat, but isnt drawing fuel from the tank...now the kinked line may be the issue...if the fuel tank isnt air tight will that impact its ability to pull fuel if the fuel line isnt 100% submerged?

Feels good to know the saw runs at least after the effort to rebuild it all and I can sort out these little peripheral issues .

Starving fuel or a leak in the fuel system has burned up plenty of saws ,aka dont run it or it'll scorch the piston and cylinder.

 

[Maintenance supervisor]

Apologies from a newb if this had been answered further back in the thread:

Do new guide bars with the D176 mount bolt right on to the midsize late model macs like the pm 10-10, pm 700, sp 81, etc? Or do you still need to bubba them up to get oil to the chain?

Also, are Internet the rumors of someone making full wrap top handles over here true?

D176 is 100% bolt on and go.
Mark H. Has full wrap handles for sale that are very nice ,requiring some clutch cover mods depending on model.

 

[Greyman]

D176 is 100% bolt on and go.
Mark H. Has full wrap handles for sale that are very nice ,requiring some clutch cover mods depending on model.

Awesome, thank you.

 

[Little Jerrry]

Thanks for the input...it's only running with fuel down the throat and only runs for a few seconds so definitely not going to hurt it - but it does rev up and idle....just got to get it pulling fuel from the tank...I had rebuilt the carb but I'll take another look, luckily kits are cheap.

Is there any way to tell if the vacuum is operating the carby correctly to pull fuel in? Or do I just have to prime the carby and see what it does? This saw doesn't have an impulse line like the old Stihl I have so not sure how to tell if it's doing its thing or has a leak.

 

[Maintenance supervisor]

Thanks for the input...it's only running with fuel down the throat and only runs for a few seconds so definitely not going to hurt it - but it does rev up and idle....just got to get it pulling fuel from the tank...I had rebuilt the carb but I'll take another look, luckily kits are cheap.

Is there any way to tell if the vacuum is operating the carby correctly to pull fuel in? Or do I just have to prime the carby and see what it does? This saw doesn't have an impulse line like the old Stihl I have so not sure how to tell if it's doing its thing or has a leak.

Impluse port is under the carb amd part of the intake, check your gasket alignment and fuel never leaks from the carburetor if rebuilt correctly. You might just need to flip a gasket or something.